1. Field of the Invention
The present invention relates to a picture recording apparatus in which magnetic fluid or powder is applied to a belt to form magnetic rise elements thereon. The magnetic rise elements are distributed at a certain spatial frequency, and are caused to flow or fly by an electrostatic force or magnetic force to provide a picture on a recording sheet.
2. Description of the Prior Art
In a conventional picture recording apparatus of this type, as shown in FIG. 1, a recording sheet 8 is interposed between a multiple stylus electrode assembly 3 and a belt 1, and magnetic fluid or powder applied to the belt is caused to flow or fly to the recording sheet according to an input signal applied to the multiple stylus electrode assembly 3, to form a picture on the recording sheet 8. In the conventional apparatus, the distance between the top of each of the rise elements 2 which are formed by the magnetic fluid or powder and the multiple stylus electrode assembly 3 is the sum of the thickness of the recording sheet 8 and the clearance between the top of the rise element 2 and the recording sheet 8. In general, the recording sheet 8 is about 100 .mu.m in thickness. The clearance between the recording sheet 8 and the rise element top must be 50 to 100 .mu.m. Thus, the distance between the rise element top and the multiple stylus electrode assembly is, in general, 150 to 200 .mu.m.
In this case, the recording density is usually of the order of the distance between the rise element top and the multiple stylus electrode assembly; i.e., it is of the order of 5 to 7 pieces/mm. Even if the electrode density of the multiple stylus electrode assembly is increased, the degreee of density of the resultant picture cannot be improved because the pitch is determined by the above-described thickness.
That is, the conventional apparatus suffers from a drawback that the recording density or resolution is low.